ok so I've drawn a 2d sketch, I then try to end sketch and "Can not rebuild the feature using this sketch". I choose the show the problem using check sketch option. It then says the sketch has no contour geometry to try to fix.. press ok. So I click ok. Default gaps smaller then setting is 0.0241069 and there's no problems found. I raise this to 800mm and 1 problem alerts "a small entity". A line is circled in yellow in the centre of it. i zoom in all the way and there are no breaks in the line and it is joined at the ends properly. I don't know what to do!!! I'm teaching myself how to use solid works and it's very frustrating! I've tried redrawing it, opening new sheets, restarting it.. nothing! Also I can't get a circle to snap properly to a line. Even drawing a simple circle then drawing a line to end on the circle it snaps on but when I zoom in it's actually not toucing or its over lappin. If I then try to trim it the whole line disappears. Please I've literally spent hours trying to fix this.

OK, I've added the fine hopefully it works. yeah i was taking the pictures on my phone, it was easier at the time. Thanks for the help in advance guys, its really not the easiest thing to teach myself without having someone i can quickly talk to whenever i don't understand something. Plus i'm not the most computer savvy guy at the best of times ha ha.

Staying focused on your problem. I found nothing wrong with your sketch to prevent it from creating an extruded feature.

The first thing I noticed is that you were trying to do the extrude as a contour (the shaded 5 sided polygon with a hole in it next to Sketch 1 indicates the feature was made using contours .

I suppose this was because some of the sketch problems you described in your original post (SolidWorks defaults to using contours when it does not find a closed sketch) caused SolidWorks to try and make the feature using contours.

The reason, after you fixed your sketch, it did not extrude properly is because the contour was lost.

Or if you do not want to use contours; delete the extrude feature and add a new one.

How you model is a matter of personal preference. Certainly keeping things simple when you are first learning is good advice as are the rest of the points J Mather makes. The only one I have issue with is adding fillets as separate features (my opinion). On simple sketches or models that have just one extrude, I would recommend putting them in the sketch. One more complicated models, I would recommend putting the fillets in as features. As I first stated, how you model is a personal preference. As you use it more you will find when it is better to model one way over another. How complicated you make you sketches depends on who will have to use them later. If it is you then no problem. If it is other users then take care you do not make your sketches so they are difficult to edit. And always fully define a sketch (lines and arcs turn black).